[CMake] Use libtool for runtimes when building for Apple platform

[phosek]

Summary

LLVM CMake build already uses libtool instead of ar when building
for Apple platform and we should be using the same when building
runtimes. To do so, this change extracts the logic for finding
libtool into a separate file and then uses it from both the LLVM
build as well as the LLVM runtimes build.

[mcgrathr]

lgtm

llvm/trunk/CMakeLists.txt

project(LLVM
   VERSION ${LLVM_VERSION_MAJOR}.${LLVM_VERSION_MINOR}.${LLVM_VERSION_PATCH}
   LANGUAGES C CXX ASM)
 
 if (NOT CMAKE_BUILD_TYPE AND NOT CMAKE_CONFIGURATION_TYPES)
   message(STATUS "No build type selected, default to Debug")
   set(CMAKE_BUILD_TYPE "Debug" CACHE STRING "Build type (default Debug)" FORCE)
 endif()
 
-# This should only apply if you are both on an Apple host, and targeting Apple.
-if(CMAKE_HOST_APPLE AND APPLE)
-  # if CMAKE_LIBTOOL is not set, try and find it with xcrun or find_program
-  if(NOT CMAKE_LIBTOOL)
-    if(NOT CMAKE_XCRUN)
-      find_program(CMAKE_XCRUN NAMES xcrun)
-    endif()
-    if(CMAKE_XCRUN)
-      execute_process(COMMAND ${CMAKE_XCRUN} -find libtool
-        OUTPUT_VARIABLE CMAKE_LIBTOOL
-        OUTPUT_STRIP_TRAILING_WHITESPACE)
-    endif()
-
-    if(NOT CMAKE_LIBTOOL OR NOT EXISTS CMAKE_LIBTOOL)
-      find_program(CMAKE_LIBTOOL NAMES libtool)
-    endif()
-  endif()
-
-  get_property(languages GLOBAL PROPERTY ENABLED_LANGUAGES)
-  if(CMAKE_LIBTOOL)
-    set(CMAKE_LIBTOOL ${CMAKE_LIBTOOL} CACHE PATH "libtool executable")
-    message(STATUS "Found libtool - ${CMAKE_LIBTOOL}")
-
-    execute_process(COMMAND ${CMAKE_LIBTOOL} -V
-      OUTPUT_VARIABLE LIBTOOL_V_OUTPUT
-      OUTPUT_STRIP_TRAILING_WHITESPACE)
-    if("${LIBTOOL_V_OUTPUT}" MATCHES ".*cctools-([0-9.]+).*")
-      string(REGEX REPLACE ".*cctools-([0-9.]+).*" "\\1" LIBTOOL_VERSION
-        ${LIBTOOL_V_OUTPUT})
-      if(NOT LIBTOOL_VERSION VERSION_LESS "862")
-        set(LIBTOOL_NO_WARNING_FLAG "-no_warning_for_no_symbols")
-      endif()
-    endif()
-
-    foreach(lang ${languages})
-      set(CMAKE_${lang}_CREATE_STATIC_LIBRARY
-        "\"${CMAKE_LIBTOOL}\" -static ${LIBTOOL_NO_WARNING_FLAG} -o <TARGET> \
-        <LINK_FLAGS> <OBJECTS> ")
-    endforeach()
-  endif()
-
-  # If DYLD_LIBRARY_PATH is set we need to set it on archiver commands
-  if(DYLD_LIBRARY_PATH)
-    set(dyld_envar "DYLD_LIBRARY_PATH=${DYLD_LIBRARY_PATH}")
-    foreach(lang ${languages})
-      foreach(cmd ${CMAKE_${lang}_CREATE_STATIC_LIBRARY})
-        list(APPEND CMAKE_${lang}_CREATE_STATIC_LIBRARY_NEW
-             "${dyld_envar} ${cmd}")
-      endforeach()
-      set(CMAKE_${lang}_CREATE_STATIC_LIBRARY
-        ${CMAKE_${lang}_CREATE_STATIC_LIBRARY_NEW})
-    endforeach()
-  endif()
-endif()
-
 # Side-by-side subprojects layout: automatically set the
 # LLVM_EXTERNAL_${project}_SOURCE_DIR using LLVM_ALL_PROJECTS
 # This allows an easy way of setting up a build directory for llvm and another
 # one for llvm+clang+... using the same sources.
 set(LLVM_ALL_PROJECTS "clang;clang-tools-extra;compiler-rt;debuginfo-tests;libclc;libcxx;libcxxabi;libunwind;lld;lldb;llgo;openmp;parallel-libs;polly;pstl")
 set(LLVM_ENABLE_PROJECTS "" CACHE STRING
   "Semicolon-separated list of projects to build (${LLVM_ALL_PROJECTS}), or \"all\".")
 if( LLVM_ENABLE_PROJECTS STREQUAL "all" )
if(NOT LLVM_CSPROFILE_FILE_PATTERN)
     file(TO_NATIVE_PATH "${LLVM_CSPROFILE_DATA_DIR}/%${LLVM_PROFILE_MERGE_POOL_SIZE}m.profraw" LLVM_CSPROFILE_FILE_PATTERN)
   endif()
 endif()
 
 if (LLVM_BUILD_STATIC)
   set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -static")
 endif()
 
+# Use libtool instead of ar if you are both on an Apple host, and targeting Apple.
+if(CMAKE_HOST_APPLE AND APPLE)
+  include(UseLibtool)
+endif()
+
 # Override the default target with an environment variable named by LLVM_TARGET_TRIPLE_ENV.
 set(LLVM_TARGET_TRIPLE_ENV CACHE STRING "The name of environment variable to override default target. Disabled by blank.")
 mark_as_advanced(LLVM_TARGET_TRIPLE_ENV)
 
 set(LLVM_ENABLE_PER_TARGET_RUNTIME_DIR OFF CACHE BOOL
   "Enable per-target runtimes directory")
 
 # All options referred to from HandleLLVMOptions have to be specified

llvm/trunk/cmake/modules/UseLibtool.cmake

+# if CMAKE_LIBTOOL is not set, try and find it with xcrun or find_program
+if(NOT CMAKE_LIBTOOL)
+  if(NOT CMAKE_XCRUN)
+    find_program(CMAKE_XCRUN NAMES xcrun)
+  endif()
+  if(CMAKE_XCRUN)
+    execute_process(COMMAND ${CMAKE_XCRUN} -find libtool
+      OUTPUT_VARIABLE CMAKE_LIBTOOL
+      OUTPUT_STRIP_TRAILING_WHITESPACE)
+  endif()
+
+  if(NOT CMAKE_LIBTOOL OR NOT EXISTS CMAKE_LIBTOOL)
+    find_program(CMAKE_LIBTOOL NAMES libtool)
+  endif()
+endif()
+
+get_property(languages GLOBAL PROPERTY ENABLED_LANGUAGES)
+if(CMAKE_LIBTOOL)
+  set(CMAKE_LIBTOOL ${CMAKE_LIBTOOL} CACHE PATH "libtool executable")
+  message(STATUS "Found libtool - ${CMAKE_LIBTOOL}")
+
+  execute_process(COMMAND ${CMAKE_LIBTOOL} -V
+    OUTPUT_VARIABLE LIBTOOL_V_OUTPUT
+    OUTPUT_STRIP_TRAILING_WHITESPACE)
+  if("${LIBTOOL_V_OUTPUT}" MATCHES ".*cctools-([0-9.]+).*")
+    string(REGEX REPLACE ".*cctools-([0-9.]+).*" "\\1" LIBTOOL_VERSION
+      ${LIBTOOL_V_OUTPUT})
+    if(NOT LIBTOOL_VERSION VERSION_LESS "862")
+      set(LIBTOOL_NO_WARNING_FLAG "-no_warning_for_no_symbols")
+    endif()
+  endif()
+
+  foreach(lang ${languages})
+    set(CMAKE_${lang}_CREATE_STATIC_LIBRARY
+      "\"${CMAKE_LIBTOOL}\" -static ${LIBTOOL_NO_WARNING_FLAG} -o <TARGET> <LINK_FLAGS> <OBJECTS>")
+  endforeach()
+endif()
+
+# If DYLD_LIBRARY_PATH is set we need to set it on archiver commands
+if(DYLD_LIBRARY_PATH)
+  set(dyld_envar "DYLD_LIBRARY_PATH=${DYLD_LIBRARY_PATH}")
+  foreach(lang ${languages})
+    foreach(cmd ${CMAKE_${lang}_CREATE_STATIC_LIBRARY})
+      list(APPEND CMAKE_${lang}_CREATE_STATIC_LIBRARY_NEW
+           "${dyld_envar} ${cmd}")
+    endforeach()
+    set(CMAKE_${lang}_CREATE_STATIC_LIBRARY
+      ${CMAKE_${lang}_CREATE_STATIC_LIBRARY_NEW})
+  endforeach()
+endif()

llvm/trunk/runtimes/CMakeLists.txt

if(${CMAKE_SOURCE_DIR} STREQUAL ${CMAKE_CURRENT_SOURCE_DIR})
   # Handle common options used by all runtimes.
   include(AddLLVM)
   include(HandleLLVMOptions)
   include(FindPythonInterp)
 
   # Remove the -nostdlib++ option we've added earlier.
   string(REPLACE "-nostdlib++" "" CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS}")
 
+  # Use libtool instead of ar if you are both on an Apple host, and targeting Apple.
+  if(CMAKE_HOST_APPLE AND APPLE)
+    include(UseLibtool)
+  endif()
+
   # This can be used to detect whether we're in the runtimes build.
   set(RUNTIMES_BUILD ON)
 
   foreach(entry ${runtimes})
     get_filename_component(projName ${entry} NAME)
 
     # TODO: Clean this up as part of an interface standardization
     string(REPLACE "-" "_" canon_name ${projName})